This invention relates to a method for synthesizing silicon compounds that contain a substituent bonded to silicon through Si--C bond. This method is undertaken for the purposes of property improvement and imparting reactivity and proceeds through the reaction of unsaturated compounds with silane compounds.
The hydrosilylation reaction is a generally applicable method for the chemical modification of organic compounds by silane compounds. This method employs hydrosilylation between SiH-functional silane and an unsaturated bond-bearing organic compound and is applicable to a fairly broad range of SiH-functional compounds and unsaturated bond-bearing organic compounds. Platinum and rhodium catalysts are generally used to run the hydrosilylation reaction in industrial or commercial processes. Since these metals are very expensive, it is crucial that the catalytic efficiency in the hydrosilylation reaction also be very high. In addition, the hydrosilylation reaction is frequently accompanied by competing side reactions and may include reaction pathways that produce a number of isomers. As a consequence, the hydrosilylation reaction is generally accompanied by such catalyst-related issues as product yield, product selectivity, and production of a single isomer. Modification of the catalyst can be carried out in order to address these problems and issues. For example, various ligands can be added and/or chemically bonded to the catalyst, or the catalyst can be immobilized on any of various different supports. However, these chemical and physical modifications are typically problematic, for example, (1) their effects may rapidly disappear and (2) an improved catalytic selectivity is generally accompanied by a lower activity. In addition, since platinum catalysts gradually lose their activity under oxygen-free conditions, implementation of the hydrosilylation reaction in the presence of oxygen becomes unavoidable thereby increasing side reactions and risk of fire.
With regard to the platinum-catalyzed hydrosilylation reaction between SiH-functional silicon compounds and unsaturated group-bearing organic compounds, the object of the present invention is to introduce a reaction method that provides a high catalyst activity and stability and that also provides a high positional selectivity in the hydrosilylation reaction product. An additional object is to achieve these features without the addition of oxygen and thereby reduce the risk of fire and explosion in the hydrosilylation reaction.